Process for preparing the ethynyl carbinol of beta-ionone



Patented June 7, I949 UNITED STATES PROCESS FOR PREPA CARBINOL O RINGTHE ETL F fi-IONONE tion of New Jersey No Drawing. Application March 19,1946, Serial No. 655,607

1 Claim. (Cl. 260617) This invention relates producing organic compoundsand more particu- In one of its more specific aspects, this invention isdirected to novel methods for producing a-ethynyl (,B-ionol).

Prior to this invention duce a-ethynyl (,B-ionol).

others proposed to pro- For the production of S. Patent No. 2,425,201, Ihave shown that a yield of ix-ethynyl (c-ionol) of approximately 67% oftheoretical could be obtained by reacting fi-ionone with calciumacetylide. In the course of my other experimentations in an effort toincrease the yield of a-ethynyl (c-ionol), I have discovered that thisyield may be increased as high as and higher than 80% of theoreticalbased on the quantity of unrecovered ,B-ioncne. Such high yields may beobtained by reacting c-ionone with lithium acetylide. According to thisinvention, c-ionone is reacted with lithium acetylide in an inertsolvent such as liquid ammonia (NI-I3), benzene, petroleum ether,naphtha, diethyl amine, ethyl ether, dioxane, the Carbitol ethers, etc.The ratio of reactants may vary, but ordinarily equimolecular quantitiesmay be employed. This reaction takes one to three hours The followingdetailed procedure is one manner of practicing this invention and isgiven by way of illustration and not limitation.

The lithium acetylide may be prepared in a number of different ways.Merely for the purpose of illustration, I shall describe a method formakin it in liquid ammonia. 700 cos. of liquid ammonia may bemechanically stirred in a glass reaction vessel, externally cooled bymeans of solid carbon dioxide or the like to maintain the temperature ofthe liquid ammonia below 40 C. The liquid ammonia is maintained at saidtemperature while a swift stream of dry, acetonefree acetylene gas isintroduced to said liquid ammonia simultaneously with 8 grams ofcomminuted freshly-cut lithium metal. Stirring of the mass and amoderate passage of acetylene are continued for an additional 20 minutesafter the introduction of all of the lithium metal particles. Throughoutthe entire period of these various additions, the temperature of themass is maintained below 40 C. and preferably at C. By following thisprocedure, the lithium acetylide is formed and dispersed in the liquidammonia solvent. Ordinarily, most of said lithium acetylide is dissolvedbut some of it may remain in suspension in the liquid ammonia. This,however, does not affect the reaction in any way.

The lithium acetylide may be readily reacted with ,B-ionone by addingthe ,B-ionone gradually to said solution of lithium acetylide in saidliquid ammonia and maintaining the temperature of the reacting mass atabout -40 C. However, in order to provide even better yields and toincrease the homogeneity of the reaction mixture, any anhydrous amine aswell as commercially available absolute ether may be added to saidsolution of lithium acetylide in said liquid ammonia before the additionof the ,B-ionone.

In the practice of this invention, I prefer to add to said solution oflithium acetylide in ammonia, about 350 cos. of anhydrous diethyl amine.Then to this solution is gradually added over about a 15-minute period,192 grams (1 mole) of pure p-ionone having index of refraction at 0 C.of 1.5205. This addition of ,c-ionone is made while diethyl ether isadded in portions to said mass in said vessel to maintain the desiredfluidity. Subsequently, 700 ccs. cold water are added slowly in smallincrements. Then glacial acetic acid is slowly added until the mass isjust slightly acid or neutral. The temperature otthe mass -during saidwater and ac etic acid addition is maintained below 15 C. and at about10 C. The stirring is then stopped and the mass is allowed to stand andits temperature increases to aboutroo n temperature whereupon itseparates into two mainlayers, an ether layer and a water layer. Theether layer is separated from the water layer. water layer may beextracted with ether and the etherlayers may be combined. The combinedether layers may be washed with water, dried over anhydrous potassiumcarbonate and then distilled to Qeyapm rate off the ether. After theether has been evaporated therefrom, the mass is distilledandtheiiistillate is collected and'lonly a negligible residue re nsh clected d s ll m asures a p o im e 29 rams and is a ixtur B- ionone anda-ethynyl (fl -ionol) which ;may be separatedfrom ea h other inanyoneofavnumber of difierent ways. For example, this distillate mixture may bedissolved .in aqueous methanolic solution with 40 ccsof semi-,carbizideand 2 cos. of glacial acetic acid and allowed-to .standovernight. Thenthe resultant mass is poured .into .a

large volume .of water whereby the unreacted B- ionone in said.distillateconverted into semi-carbazone precipitates .out as a solidand .is mixed with the wethynyl .(p-ionol) which is an .oily liquid.This mixture is then shaken with petroleum ether whereupon the u-ethynylS-ionol) is selectively dissolved and the solid fi-ionone semi-carbazoneremains suspended in this solution. .The mass is allowed to stand and anaqueous layer separates out. The aqueous layer is removed and thepetroleum ether mixture is filto 149 troleum ether.

aforedescribed procedure tered free of the car-bazone. The filtrate isrecovered and first freed of the petroleum ether and then furtherdistilled and the distillate collected is substantially pure a-ethynyl(,e-ionol) measuring 155 grams, having a boiling point of about ionol)is more this invention.

I claim: A method for producing a-ethynyl (fl-ionol) comprising in aninert solvent reacting lithium acetylide with fio a d ihvd q vzin aha-rsultant reaction product.

REFERENCES 01 31) The following references are of recordi-n the file ofthis patent:

UN S TE .BA'IENTS Name Date Milas Feb. 13, 19,46

OTHER REFERENQE Heilbron et al.: J our. Chem. 'Soc.,;London 191,4, pages144-7.

Davies et al.: J our. Chem.-Soc. (1935) .58?- Campbell et al.: Chem. Abs'vol. 35,55i-57 (1941). Johnson: Acetylenic Compounds, -vol. '1,Acetylenic Alcohols. Pub. by Edward Arnold $1 69., London (1946) 11-14and 341-2.

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